Epileptiform activity during opioid anesthesia

Emergency Interventions After Severe Traumatic Brain Injury in Rats: Effect on Neuropathology and Functional Outcome

“…We have previously demonstrated that the hippocampus and cortex ipsilateral to the impact show marked flow reduction (at least 60%) at 2 hours after TBI in the controlled cortical impact model. 25 Cerebral blood flow approaches ischemic levels in the 3 ) was calculated as the sum of these areas in each group and is depicted as the cumulative volume (right y-axis) in the normal ventilation (triangles) and hyperventilation (squares) groups. There was no difference between groups in contusion volume (normal ventilation, 27.8 ± 5.1 mm 3 compared with hyperventilation, 27.8 ± 3.1 mm 3 , mean ± SEM).…”

“…Rats were equilibrated under anesthesia (1.196 isoflurane/66% N 2 0/balance oxygen) at a brain temperature of 37°C ± 0.5°C for 30 mins before TBI. An arterial blood sample (0.5 mL) was obtained 15 mins before trauma to verify normal arterial blood gas tensions, serum glucose, and hematocrit TBI was performed using the CCI device (23,24), with minor modifications to the procedure previously described (25). Briefly, after removal of the bone flap, injury was produced using a device with a 6-mm metal impactor tip that is pneumatically driven in the vertical plane at a predetermined depth, velocity, and duration of brain deformation.…”

“…Support: USAreay#DAMDI7-»7-I-7009 SOCIETY FOR NEUROSCIENCE. VOLUME 25,1999 was kept between 30-35 mmHg for 30 min, with 56% nitrous oxide, 31% nitrogen, and 13% oxygen. Pa0 2 in the normoxic group was maintained over 100 mmHg, while PaC0 2 in all rats was maintained at 35-40 mmHg.…”

“…Opioids generally suppress neuronal excitability, however, mu receptor agonists, such as fentanyl, may contribute to hippocampal neuron excitation (Bradley and Brookes, 1984;Neumaier and Chavkin, 1986;Neumaier et al, 1988). In fact, high-dose fentanyl (25 -100 ug/kg in humans and 400 ug/kg in rats) has been associated with subcortical seizures (Faden et al, 1985;Kearse et al, 1993;Mclntosh et al, 1986;Ohta et al, 1995;Safo et al, 1985;Tempelhoffet al, 1992). Although fentanyl exhibits low affinity for kappa receptors (Ohta et al, 1995), kappa receptor antagonists have been shown to improve both neurological outcome after spinal cord injury and CBF after fluid-percussion injury in cats (Faden et al, 1985;Mclntosh et al, 1986).…”

Effect of Fentanyl on Lidocaine-Induced Convulsions in Mice

“…Tommasino et al [26] showed a hypermetabolism in the limbic structure in rats with epileptoid activity by intravenous fentanyl administration. In humans, epileptiform activity caused by fentanyl and sufentanil administration has also been reported [27] . Tempelhoff et al [28] found that, in patients with complex partial seizures, fentanyl elicited electrical seizure activity in both the ipsilateral and contralateral (healthy) temporal lobes.…”